org.to2mbn.jmccc.mojangapi.io.MultipartBuilder Maven / Gradle / Ivy

Go to download
package org.to2mbn.jmccc.mojangapi.io;

import org.to2mbn.jmccc.util.HexUtils;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.nio.charset.Charset;
import java.security.SecureRandom;

public class MultipartBuilder {

    private static final SecureRandom RANDOM = new SecureRandom();

    private static final int READY = 0;
    private static final int DISPOSITION = 1;
    private static final int HEADERS = 2;
    private static final int FINISHED = 3;
    private String boundary = randomBoundary();
    private ByteArrayOutputStream out = new ByteArrayOutputStream();
    private Writer writer = new OutputStreamWriter(out, Charset.forName("UTF-8"));
    private int status = READY;

    private static String randomBoundary() {
        byte[] rnd = new byte[8];
        RANDOM.nextBytes(rnd);
        return "---------------------------" + HexUtils.bytesToHex(rnd);
    }

    public String getBoundary() {
        return boundary;
    }

    public String getContentType() {
        return "multipart/form-data; boundary=" + boundary;
    }

    public MultipartBuilder disposition(String key, String value) throws IOException {
        if (status != READY && status != DISPOSITION) {
            throw new IllegalStateException("The current status is " + status + ", expected: " + READY + " or " + DISPOSITION);
        }

        if (status == READY) {
            status = DISPOSITION;
            writer.write("--");
            writer.write(boundary);
            writer.write("\r\nContent-Disposition: form-data");
        }

        writer.write("; ");
        writer.write(key);
        writer.write("=\"");
        writer.write(value);
        writer.write("\"");

        return this;
    }

    public MultipartBuilder header(String key, String value) throws IOException {
        if (status != DISPOSITION && status != HEADERS) {
            throw new IllegalStateException("The current status is " + status + ", expected: " + DISPOSITION + " or " + HEADERS);
        }

        if (status == DISPOSITION) {
            status = HEADERS;
            writer.write("\r\n");
        }

        writer.write(key);
        writer.write(": ");
        writer.write(value);
        writer.write("\r\n");

        return this;
    }

    public MultipartBuilder content(byte[] payload) throws IOException {
        if (status != DISPOSITION && status != HEADERS) {
            throw new IllegalStateException("The current status is " + status + ", expected: " + DISPOSITION + " or " + HEADERS);
        }

        if (status == DISPOSITION) {
            writer.write("\r\n");
        }
        status = READY;

        writer.write("\r\n");
        writer.flush();
        out.write(payload);
        writer.write("\r\n");

        return this;
    }

    public byte[] finish() throws IOException {
        if (status != READY) {
            throw new IllegalStateException("The current status is " + status + ", expected: " + READY);
        }
        status = FINISHED;

        writer.write("--");
        writer.write(boundary);
        writer.write("--\r\n");
        writer.flush();
        return out.toByteArray();
    }

}